Zaph SR71 kit with Parts Express 0.50 cu. ft. cabinet - compatible combination?

[swegen]

Take heed that i'm quite new to this so i'm looking for a basic walkthrough from those with more experience. My only experience so far is putting together a flatpack kit from DIY Sound Group.

I'm now planning on doing 5 Zaph SR71's for a small bedroom home theater, using one as a center channel placed on it's side, but my only dilemma is the cabinet/baffle situation. I have close to no tools at my disposal -- no wood saw or router, and it seems that Madisound is no longer offering pre-built cabinets or pre-cut baffles for the SR71. I've read that these .5 cubic ft. cabinets from Parts Express will work just fine as it's the same volume as noted in John's design and close to the same dimensions.

Correct me if i'm wrong but i'm assuming all that needs to be done is to route(?) holes in the rear for the port and binding-post terminal cup, and then of course route the holes for the tweeter and woofer on the provided blank baffle. My plan is to take these 5 cabs to a cabinet maker or dedicated speaker builder here in LA to route the holes for me as i'm guessing this may be cheaper and most importantly, more foolproof than buying a router/jig and doing it myself.

A few questions:
-First off, are there any objections to using these Parts Express cabinets with the ZR71 kits or will they work together just fine?
-I'm kind of worried about the port and terminal cup holes that need to be routed at the back of the cabs. Is there a good chance of ruining the cabinet by cutting into the high-gloss finish?
-Since i'll be using a slightly different cabinet than John's design, are there any modifications that'll need to be made to the provided port? (note that i'll be crossing over at 80Hz to a subwoofer to cover the low bass.)

Any help would be appreciated.

 

[Einric]

Routing in the High Gloss will be fine if you use masking tape to protect the finish & minimize chip-out.

 

[Richard Ellis]

The Seas 7" driver here models in at 14.9 liters best....Your cabinet at 14.16 liters is way close. Plugging in the numbers for your cabinet of choice gets us an F3 of a hair over 52 Hz(couldn't get the cursor "on" -3 Db exactly).
Porting at 47mm diameter by 130 mm long.....now this doesn't take into account volume of the driver backside, nor the "port pipe" but that can be calculated, plugged back into the simulation to get a more refined calculation.
Either way it's well below your crossover to the sub-woofer.
It'll work just fine!!

________________________________________________________Rick.........

 

[JohnGeneva]

I used the blank madisound front panels on my SR71 build and routed the driver holes after I put masking tape to cover the front. This worked very well and avoided all chipouts on the finish. The circle cutting jig is not that expensive if you can borrow a router. I am really happy with mr SR71s, using them in our small apartment they sound awesome.

 

[Richard Ellis]

You have a supplied port? We would need to know the internal dimensions of said port, and the length. Taking the volume of the rear of the driver and the port tube into consideration, it would make it less volume still....but your going to add fill into the box which thru the adiabatic process makes the box *appear* 10-15 % larger..... your right on target with the volume.


________________________________________________________Rick..............

 

[ODougbo]

I built of SR71s, so did my buddy - his worked better with the flare port.

I highly recommend finding someone to cut boxes for you, the size is part of the design.

Where are you located Swegen?


btw....good info in here, check post #95 as a really good box example: http://www.diyaudio.com/forums/multi-way/213397-zaph-audio-za-sr71-review.html

 

[swegen]

Appreciate the info and masking tape tip.

You have a supplied port? We would need to know the internal dimensions of said port, and the length. Taking the volume of the rear of the driver and the port tube into consideration, it would make it less volume still....but your going to add fill into the box which thru the adiabatic process makes the box *appear* 10-15 % larger..... your right on target with the volume.

The port that comes with the added accessories option in the Madisound kit is this 2" (50.8mm) diameter flared port: The Madisound Speaker Store

The description says to cut the tube to 2.25" in length so it'll be 3.25" (82.55mm) total.

I built of SR71s, so did my buddy - his worked better with the flare port.

I highly recommend finding someone to cut boxes for you, the size is part of the design.

Where are you located Swegen?

I'm in the US, specifically Los Angeles, California. I haven't looked around yet but i'm guessing it shouldn't be hard to find someone to route the holes for me. Unfortunately I don't know anyone that has a router for me to borrow. 4 cuts a cabinet x 5 cabinets i'm assuming shouldn't take too long so i'm thinking the cost of labor won't be unreasonable, but i've no experience with woodworking so I may be completely off base. Trying to be as economical as possible and i also love the look of those PE gloss cabs.

 

[ODougbo]

Can't open PE link - however, it would be really wise to round over the edges on you new boxes.
It's not hard to build them, however need several tools/bits and clamps.
The SR71s came with plans - yes?

 

[DEQXter]

Appreciate the info and masking tape tip.



The port that comes with the added accessories option in the Madisound kit is this 2" (50.8mm) diameter flared port: The Madisound Speaker Store

The description says to cut the tube to 2.25" in length so it'll be 3.25" (82.55mm) total.



I'm in the US, specifically Los Angeles, California. I haven't looked around yet but i'm guessing it shouldn't be hard to find someone to route the holes for me. Unfortunately I don't know anyone that has a router for me to borrow. 4 cuts a cabinet x 5 cabinets i'm assuming shouldn't take too long so i'm thinking the cost of labor won't be unreasonable, but i've no experience with woodworking so I may be completely off base. Trying to be as economical as possible and i also love the look of those PE gloss cabs.

Swegen--hi. I also bought some of the PE cabs--only the 1.0 cu ft version and while I have a router (cheap craftsman with fixed base) not so sure of my skills and the layout is somewhat demanding. I found a cabinet company with CNC here in Albuquerque and waiting for a quote. Like the cabs a lot--may need to brace mine some more owing to the tall side panels and meager amount of material left on the baffles between drivers but overall am pleased. One place you could save some potential cash is foregoing the terminal cups altogether and using the provided holes to knock in some posts. Guess it all depends on the quote you get.

Anyhow good luck from one noob to another. Be interested in hearing the quote you get.

 

[swegen]

Can't open PE link - however, it would be really wise to round over the edges on you new boxes.
It's not hard to build them, however need several tools/bits and clamps.
The SR71s came with plans - yes?

The PE website was down but it's this:

Putting together my first flatpack kit with success got me hooked so i'll definitely be delving into building my own cabinets sometime in the future. For these SR71s, I don't think I can accomplish the same level of finish as the PE cabs until I acquire more experience and eventually all the tools needed.

Swegen--hi. I also bought some of the PE cabs--only the 1.0 cu ft version and while I have a router (cheap craftsman with fixed base) not so sure of my skills and the layout is somewhat demanding. I found a cabinet company with CNC here in Albuquerque and waiting for a quote. Like the cabs a lot--may need to brace mine some more owing to the tall side panels and meager amount of material left on the baffles between drivers but overall am pleased. One place you could save some potential cash is foregoing the terminal cups altogether and using the provided holes to knock in some posts. Guess it all depends on the quote you get.

Anyhow good luck from one noob to another. Be interested in hearing the quote you get.

Likewise, at this stage i'm unsure of my capacity to get clean, precise, and dead-center cuts and I also figured CNC may be an option. I'll have to investigate around for quotes. I wasn't sure if the PE cabs provided holes for the terminals but if that's the case, I may just bypass installing the cups.

I actually own a pair of those 1.0 cu. ft. PE gloss cabs (the curved version) that utilizes the same Seas ER18RNX woofer as the SR71, but with a Fountek ribbon Neo CD3 tweeter. It was designed and built by a very competent speaker maker. The woofer is what piqued my interest towards the SR71, really love the sound it puts out.

 

[tvrgeek]

I too really like the woofer.

The design is very critical on the driver placement and the box edges. I rounded all 12 edges at 3/4 inch and it smoothed out very well.

I would up changing the tweeter to the aluminum dome version and adding a felt ring to the baffle. The crossover amazingly wound up exactly as John designed. We just liked the little extra top end from the other tweeter. Maybe we are just getting old and need the help. I used the soft domes in a set of Daytons I was redoing. Nothing wrong with them.

I did not use the cups. Junk IMHO. I use through terminals. I also put a layer of no-brand Dynamat around the port tube as well as lining the box.

Never had CNC done. You can do just fine with a DIY pin base and any old cheap router. With a bit of care and some straight edges, you can cut out anything with no more than a circular saw. Museum quality furniture can be done with hand tools.

 

[ODougbo]

Since the boxes have a gloss finish, there's no question that you need a few templates, easy to make, and nearly fool proof. As many have said, woodworking is all in the prep, not a 5 minute router task.

First step is to cut you templates; Jasper setup, boards with nails, you can even super size the router base and use that with a nail. This could take a while to get the holes down to 1 mm tolerance.

As shown in pic, make a template to custom fit your work piece.

Need a good lam trim router, or mid-sized router. Two router bits:

1. 1/4 straight
2. Top bearing router bit. {bits can be bought on ebay - super cheap}

Saw some clamps like these at Harbor the other day, 3.99 each.

You can cut driver hole first and then come back and do the recess, or visa versa. Just do everything on top of the templates.


DON'T FORGET TO FLUSH YOUR DRIVERS!

 

[DEQXter]

. ...

....
Likewise, at this stage i'm unsure of my capacity to get clean, precise, and dead-center cuts and I also figured CNC may be an option. I'll have to investigate around for quotes. I wasn't sure if the PE cabs provided holes for the terminals but if that's the case, I may just bypass installing the cups.

I actually own a pair of those 1.0 cu. ft. PE gloss cabs (the curved version) that utilizes the same Seas ER18RNX woofer as the SR71, but with a Fountek ribbon Neo CD3 tweeter. It was designed and built by a very competent speaker maker. The woofer is what piqued my interest towards the SR71, really love the sound it puts out.

Yea, I waffled long and hard between the SEAS ER18's and the Ushers I ultimately chose--I don't think it is any accident that the guys at SB acoustics used something similar for their statement Satori line for a woofer which combines top drawer motor with strong paper. For that matter the Usher 8948a I chose also paper but with a touch of CF. Ultimately, I just wanted to use two woofers per side, and the Ushers can go sealed or ported into a cubic foot. Ported likely to begin with, then as I add subs, back to bassics! Anyhow not to hijack, best of luck--I'm taking the plunge after all (with that little fixed base router and a router buddy which looks a bit more versatile than the Jasper). Either way luck to ya and you have some mighty qualified help I see!

 

[swegen]

Again, thanks for all the advice. I decided to have the cabinets built by a third party, I found a place that's doing it for a really good price. These should be much nicer than the Parts Express cabinets. I'll post pictures once they're fully assembled.

Question....first time ever crimping, i'd like to try this first instead of soldering the terminals permanently. Is a cheap crimping tool like this fine or do I need a more expensive ratcheting one?

I'm using the Madisound quick connects:

 

[swegen]

^Went with a higher quality crimper just in case.

Gonna be putting these speakers together this week.

Question: Madisound has been phasing out their larger 630VDC ClarityCaps so they're now including smaller 250VDC ESA caps with the kit. Is this going to present any significant change to the crossover? Seems like quite a reduction in voltage.

 

[Andersonix]

How many volts will your amp put out?

 

[swegen]

I'll be running 5 of them directly using a "90wpc" Denon 2112CI, 120V outlets here.

 

[Andersonix]

Next hint: What is the cap's VAC rating?